Gf doesn't go outside much
I'm really concerned for my gf and I don't know how to express it to her. She doesn't go outside, and last time I talked to her about it, I came off rude because I'm not the best at expressing my emotions. When I talked to her about it, she used the excuse that she 'went outside yesterday' (I'm assuming she was implying that makes it fine if she doesn't go outside much?? Don't know why she really said that). She even said she would walk my dog with me every morning and afternoon, but so far has not done it or used excuses not to. (Example: she didn't take a shower yet, but when she said that I said it's better to take a shower after the walk, but she still said no)
I have no idea what to do and how to bring it up without her shutting down.
If anyone has tips, I feel I should mention that she gets overwhelmed with repeated company, even with me. (Like if I slept over at her house for two days, hanging out afterwards is a no-go) it even makes me hesitant to want to go on dates with her.
We are both minors, if thats important. (Not saying the specific ages for privacy)
Does anyone have any idea what to do?
Edit: for anyone wondering, I'm concerned because I'm aware that going outside is good mentally and physically, and since my gf doesn't get outside much, I'm worried the isolation will cause depression and heighten anxiety when going outside.